2012 v Rear Brakes Groaning/Howling when cold with video - TSB T-SB-0081-13

Thank you! Mine's out of warranty sadly due to age. I thought one of my parents forgot the parking brake and warped the rear discs. I guess it's a defect. Seems not to affect function, so I'll wait until the rear pads are worn to replace the discs with new ones I guess...

 

Try jacking up the rear (chock the front) and spin the wheels, see how that goes. They should spin "relatively" freely, definitely should not fight you.

Have the rear brakes been worked on? It's way too easy, to misalign the pattern on the rear caliper piston face with the pin on back of pad (a poor design imho). If that's happened they will drag royally. You might also see scoring on the rotor. Basically the pads are being clamped unevenly on the rotor, and the inner pad will be making little or no contact towards the rotor centre.

Check how freely they are turning and post results.

 

The car has less than 15k miles, so I want to say pretty sure no. (My parents use it and I can't be 100% sure they didn't agree to someone doing some brake work on it when I wasn't watching).

 

A Prius often gets 100k miles from a set of brakes unless someone has left the "emergency"/parking brake on too long or at too high a speed. Feel the rear rotors. How grooved are they where the pads would contact (inside and outside)?

 

I did not know the parking brake uses the disc. I guessed it is a drum type. I will check....

Thanks guys!!!!

 

I think it's the same, or a close variant of the regular 3rd gen Prius. The latter has a rear disc brake, and uses a cable-activated lever connected to the rear caliper, to push the piston out slightly, clamp the rotor with the pads.

Attachment is for regular Prius, but should be similar.

 

Hello and thank you for sharing your experience.

Does anyone know if Toyota Service Bulletins are shred and referenced internationally?

A local Aussie Toyota dealer seems unaware of the “howling/groaning” issue. There seems to be a standard “surface rust on rotors” explanation which is BS as my previous vehicles did not present this issue.

Weather conditions are not different.

The only variable is I now drive a Prius.

At cooler - an perhaps moist - ambient temperatures my idling 2016 Prius V starts howling or groaning as it coasts out the garage. The groaning ceases as I reach the drive.

A/V samples of the howling/groaning sound are available at the links below.

My initial and non-technical speculation was some moving part is not lubricated or warmed up or correctly aligned.

Note, I am hoping to get a recording of my own vehicle “groaning”.

 

I have a 2012 Prius v which I bought new in 2012 and my brakes make that noise every time it rains or I drive thru slush here in UT. It seems the rotors rust quickly and you are removing surface rust in just a short time. My car has just under 50k miles on it. Seems to be a Prius thing.

 

Are the hubs on the rotors rusty? I just purchased a used 2012 v and while the rear brakes are operable...I've never seen such rusty rotor hubs! And only on the rear rotors...very strange. My plan is to replace the rear brake rotors/pads as soon as it gets warmer this spring.

 

Ours makes that exact noise on the YouTube video, at only 18489 miles!

 

I suspect my 2016 Prius V is displaying a similar issue but my local "Bill Buckle" Toyota Service Centre dismissed my claim when I left the car with them overnight and they were apparently unable to reproduce the issue next morning.

Bill Buckle suggested I record the issue as it happens so I have compiled some footage and continue to update the clip so the most recent instances are at the beginning.

 

Seamus Warren- Yes, unfortunately, that is the sound. It is unpleasantly annoying. The good news is that it does seem to go away during the day, and doesn’t seem to affect performance. The bad news is that I’m guessing the metal in the rotors are warping over night causing it to rub the pads in the morning.

I hope they set yours straight as yours is definitely under warranty year wise at least....

 

We had that sound occasionally with our 3rd gen. Apparently just in reverse, just starting up, for a few seconds. Haven't heard it in quite a while though. Considering how fleeting it was, I couldn't get worked up about it.